Digital imaging is the representation, and storage, of an image or object as a digital raster image. Digital imaging is increasingly used in many industries, partly because of the increased availability of enabling technology and partly due to the many advantages offered over conventional storage methods including: reduced storage space, increased access speed, focused retrievability (e.g., search capabilities), the ability to conveniently make “multiple” and “backup” copies of documents, and the ability to transfer or transmit documents quickly.
In the case of paper document originals, digital imaging systems will typically scan the paper document and store a representation of the scanned document as a digital raster image. An optical scanning device is typically used to scan images of the paper originals for storing as a digital image. The scanned images are exact representations of the original (limited only by the resolution limit of the scanning device), and can include handwriting, signatures, photos, figures, etc. Alternatively, digital images originating from digital cameras, medical imaging devices, or other sources may also be stored in a digital imaging system.
One drawback of known imaging technology is the inherent ability of digital images to be altered, for example, with a purpose to defraud. For example, although an original paper document can be tampered with, such tampering (erasure or additions) will typically leave telltale evidence, digital images of those documents, on the other hand, can be perfectly altered leaving no such evidence. Thus, where the authenticity of an image is critical and may come into question (e.g., legal and medical fields), use of digital images is often not preferred, not acceptable or not admissible and therefore often avoided.
While many different digital image formats are available, in each case, the data is potentially alterable. Even if the digital imaging system does not explicitly provide an editing function, the images can be edited with a third party tool.
A proposed solution is the use of Write-Once, Read-Many (“WORM”) optical media to store digital images. One advantage of WORM media storage is that the data it houses is inherently unalterable data can be written only one time to the medium. However, this approach has several disadvantages as well. For example, data recorded on WORM media can be copied from the WORM disk of original recording to re-writable media, altered, and then recorded on new WORM disk with no traceability of such events.
Additionally, although it can be stated with great confidence that data on any one particular WORM disk has not been altered since it was recorded on that disk, the date and time when the data was recorded or whether the data matches an “original” of any kind cannot be determined with any certain or definitive means.
A known advance in file verification technology provides for registration of an “electronic signature” of a digital file (image, word processor document, audio or video clip, etc.). It is known to allow a user to locally select a file and locally run a program provided by a service provider to create an “electronic signature” of the selected digital file based solely on file content. The signature along with a user-provided file name and user-selected keywords are uploaded to He provider's site and stored in a registration database maintained by the service provider under an account established for the particular user. One particular provider generates a “certificate of registration” showing, inter alia, the signature.
Verification of content and submittal date of the digital file at a later time requires going on-line to access the service provider's site and retrieving the prior registration record by file name or keywords. The retrieved database record shows the file signature and the original date that the file signature was registered. To complete verification, the user must run (locally again) the electronic signature program on the file to be verified and compare the regenerated signature to the retrieved registered signature to determine whether the signature of the digital file in question matches that of the originally registered file.
What the user now has is verification that the signature of the file in hand matches the signature of a file which was registered on a particular date.